Patient Population
We performed a single-center, retrospective observational study of patients enrolled in a prospectively populated AF ablation database, approved by the Johns Hopkins IRB and maintained continuously at Johns Hopkins Hospital since 2002. Patients enrolled in the current investigation underwent ablation for either PAF or persAF from January 2014 through March 2019. In that period, 307 patients were identified who had received at least four weeks of continuous therapy with amiodarone for rhythm-control purposes in the one-year window prior to AF ablation. PAF patients were treated with Amiodarone at a minimum maintenance dose of 200mg per day for at least four weeks; persAF patients were treated with loading doses of amiodarone followed by maintenance dosing, and underwent electrical cardioversion (CDV) to restore NSR after at least two weeks of amiodarone therapy if necessary.
Patients were divided into two groups based on clinical response to amiodarone. The amio-success group (n=183) maintained NSR for the entirety of therapy with amiodarone and presented for PVI in NSR. The amio-failure group (n=124) included patients who were loaded for with amiodarone for a minimum of 4 weeks and cardioverted if necessary, but who nevertheless experienced either recurrent episodes of PAF or persAF.
Patient characteristics were systematically recorded and included age, gender, comorbidities, history of anti-arrhythmic use and cardioversion, AF subtype (paroxysmal, persistent, or long standing persistent), and baseline echocardiographic parameters (left atrial size and left ventricular ejection fraction [LVEF]). Procedural data including pre-procedural imaging, peri-procedural anticoagulation approach, ablation information (RF v. cryoballoon; PVI only v. PVI with non-PV targets; target power, force, and temperature parameters) were similarly recorded.
Arrhythmia recurrence and peri-procedural complications were ascertained based on monitoring strategies suggested in the consensus document [1]. Arrhythmia recurrence was defined as any AF or atrial tachyarrhythmia (AT) sustained for >30 s recorded by a surface electrocardiogram or rhythm monitoring device after a 90-day blanking period. Procedure-related complications, including vascular complications, major bleeding, phrenic nerve palsy, cerebral embolism, pericardial effusion/tamponade, atrioesophageal fistula, or extended hospitalization (>48 h) were assessed. All patients were observed in the hospital for a minimum of one-night post-ablation. Routine follow-up (history, exam, and electrocardiography) was performed at the outpatient clinic or by a local cardiologist at 3, 6, and 12 months, and additionally, if prompted by symptoms. Holter or event monitors were arranged for patients in whom symptoms suggestive of AF developed in the post-blanking follow-up period. Pacemaker interrogation records were also used for arrhythmia recurrence monitoring when available. AAD therapy, if present at the time of ablation, was discontinued at the 3-month follow-up visit based on the operator’s discretion. Reinitiation of AAD therapy post-blanking period was considered a procedural failure. Outcomes were assessed via electronic health records.